Children in Britain have begun receiving a swine flu vaccine today as part of a two-week trial.

Researchers are hoping to use about 1,000 youngsters over the next fortnight to gauge which of two different drugs perform better.

Children aged between six months and 12 years are being recruited at five test venues in Oxford, Bristol, Southampton, Exeter and London.

One of the test vaccines – made by Baxter – is still awaiting approval from the European Medicines Agency, but could be cleared to be used this week. The other, Pandemrix – made by GlaxoSmithKline – has already been approved by regulators.

Professor Andrew Pollard, a head researcher at the University of Oxford, told the BBC one of the aims of the trial was to see which drug performed better when given to children.

"We are doing this trial to compare head-to-head the two vaccines which are going to be used in the UK against swine flu to see which one works best in children and which one is best tolerated," Pollard said.

"We are sort of in a race against time because we know the flu season is already started. We hope to immunise the children over the next 10 days or so."

Government data showed the number of swine flu cases across the country nearly doubled to 9,000 in the week beginning 14 September, compared with 5,000 the week before.

Nicolette Wolf, who is pregnant, brought her 17-month-old son, Reuben, to be immunised at John Radcliffe hospital in Oxford.

"It's very important for him to get vaccinated. Obviously I am pregnant and the least chance of me getting swine flu the better," she said. "If you can have the opportunity to have the vaccine, that's a good idea."

The government is hoping to start vaccinating millions of people in high-risk groups, such as those with asthma and diabetes, and health workers, next month.

Across the UK, 82 deaths have been linked to the virus, with 70 in England, nine in Scotland, one in Wales and two in Northern Ireland.